In recent years, the establishment of an intra-company network using an IP telephone apparatus has been increased. Also, as shown in Japanese Patent Application Publication (JP-P2005-27247A), a mobile IP telephone apparatus using a wireless LAN (Local Area Network) and a mobile phone apparatus with an IP telephone function have been popularized. Since an IP telephone apparatus and the mobile phone apparatus with the IP telephone function are movable, there is a case that the apparatus belongs to a network that differs from a network to which it usually belongs.
With regard to a call reception history in the IP telephone apparatus, a technique described in Japanese Patent Application Publication (JP-P2005-191730A) is known. This related art is directed to an extension telephone which uses a fixed IP telephone apparatus and determines whether a call is from a public network or from a same network, on the basis of a call originator data when the call is received. Then, a pre-fix number “0” is added to the call originator number of a call reception history in case of the public network and the added call originator number is held, or removes a site number from the call originator number of the call reception history in case of the same network and the removed call originator number is held.
In the above-mentioned conventional IP telephone apparatus and mobile phone apparatus with the IP telephone function, unless whether a counter communication node belongs to the same network as the above telephone apparatus or the different network from the above telephone apparatus or the public network is determined and left in a call reception history when a call is received, the pre-fix number must be added to the head portion of the telephone number when the call is originated on the basis of the call reception history.
Also, in the conventional IP telephone apparatus and a mobile phone apparatus with the IP telephone function, at the time of the reception of a call from the same network as the network to which the apparatus usually belongs, a company extension number leaves as a call reception history. Also, at the time of the reception of a call from the different network, it is necessary to add a site number to the company extension number to leave as the call reception history. In this way, depending on the network to which the telephone apparatus itself belongs, it is necessary to determine whether or not the site number should be added.